1. Field of the Invention
This invention relates to fluid flow control valves, and more particularly to ferroelectric active fluid flow control valves which provide improved passage of the fluid during certain time periods and provides positive closure of the valve during other time periods.
2. Description of the Related Art
Fluid flow applications often require a valve which, during certain time periods, allows unimpeded passage of the fluid and, during other time periods, allows no passage of the fluid. A "one-way valve", also known as a "check valve", is an example of such a valve. It allows unimpeded passage of the fluid in one direction ("with the direction of flow") and no passage of the fluid in the opposite direction ("against the direction of flow").
Current check valves use the action of the reversal of fluid flow to activate the valving action, and also use electromagnetic or other actuation of the valving action. These passive check valves require the fluid flow to activate the valving action. The need for the fluid to activate the valve can lead to an undesirable amount of resistance against the fluid flow. This is lost effort which must be delivered by the pump. Also, the closure of the valve by the liquid requires an undesirable fluid volume amount (flow in the wrong direction). This "dead" space requires the pump to deliver a fluid flow volume that is wasted. Currently available active check valves require complex mechanisms to allow external electrical actuation to be effected.